Science Buddies: "Ask an Expert"

Hi Science Expert,

In an experiment my group and I are conducting we are testing to see if diffusion is affected by temperature. In our procedure we put dye into 2 glasses with equal amounts of water, yet one glass of water was hot while the other was cold.

We found that the food coloring diffused faster in cold water than in the hot water, and we were wondering if there is a reason for that? Does it have something to do with the movement of molecules in the hot/cold water? Or does it have to do with the chemical makeup of the dye itself versus the water?

Thank you

Hello,
Those are both very good questions! I'm sure there is a reason. I would suggest trying to identify what the chemical make-up of your dye is. See if there is anything in it that would keep it from diffusing in hot water.

Hope this helps get you started!
Katie

Hi there,

Katie has already given you some great advice! Since you asked about the movement of the molecules, I wanted to point out that a higher temperature means that the molecules (of the water, in this case) are moving faster, on average. Temperature is a measurement of the average kinetic energy of the molecules, and kinetic energy is the energy of movement. So it is curious that your dye diffused faster in cold water, and it may indeed have something to do with the chemical makeup of the dye.

Please post again (in this same thread) if you have more questions, and please let us know what you find out about your dye!

Heather